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RESILIENT DISTRIBUTION SYSTEMS WITH COMMUNITY MICROGRIDS

Yuan, Chen
http://rave.ohiolink.edu/etdc/view?acc_num=osu1480478081556766

Abstract Details

2016, Doctor of Philosophy, Ohio State University, Electrical and Computer Engineering.
Large-scale power outages are rare but extreme accidents. They are usually caused by severe weather events and overloading caused cascading failures. Nowadays, with climate change and ever-increasing load demand, power blackouts are happening more frequently. In order to ensure reliable power delivery to customers, resilient distribution systems are envisaged, because of their characteristics of high reliability, power quality, advanced protection, and optimal restoration. During extreme events, they can provide uninterruptible power supply to critical loads, quickly detect and accurately isolate fault areas, and reestablish with an optimal restoration plan. This dissertation first proposes to develop community microgrids within distribution systems by integrating local distributed energy resources (DERs) and neighboring load centers, especially critical loads. Community microgrids can be useful means of providing resilient electricity service by enabling sustainable operations and supporting critical loads in the event of power disruptions. When an extreme event happens, the distribution system can be seamlessly partitioned into several energy-independent community microgrids. Then, the important customers are supplied with uninterrupted power by local DERs. After fault isolation, distribution systems are restored by reconnecting these community microgrids. The DER selection for community microgrids is mainly determined by the levelized cost of energy (LCOE) based quantitative assessment in conjunction with the quality functional deployment (QFD) tool. Subsequently, the capacity planning of dispatchable generation units, like natural gas gensets and battery energy storage system (BESS), is elaborated. The goal of this sizing scheme is to keep adequate reserve margin to ride through unforeseen events, like uncertainties from loads and renewables, loss of generation, etc. This is because when community microgrids work in the islanded mode, the critical loads completely rely on the power generated by DERs. Therefore, the resource adequacy is a key requirement to handle unexpected incidents. Discrete-time Fourier transform (DTFT) and particle swarm optimization (PSO) are employed to find the optimal sizing solution by satisfying reserve margin requirement and minimizing annualized cost. The loss of load expectation (LOLE) is used to ensure the reliable operation of islanded community microgrids during blackouts. In addition, the impacts of reserve margin on system reliability and case studies with various portions of renewable generation are illustrated to provide guidance for the sizing of dispatchable generators. To ensure the resilience of distribution systems, advanced protection schemes that can fast detect and accurately isolate fault areas are needed. However, many protection challenges exist in making the shift away from conventional distribution systems. For example, with large penetrations of DERs and microgrids, the power flow within a distribution system becomes bi-directional and the fault current level varies significantly. In this dissertation, a multilayered protection strategy is presented for distribution systems with community microgrids. The proposed strategy is verified by simulation studies in MATLAB/Simulink against various fault conditions. A comparison between the proposed strategy and existing distribution protection schemes is also provided. After fault isolation, because of the radial topology in distribution systems, the loads downstream are interrupted. Therefore, a modified Viterbi algorithm is presented to identify the optimal distribution system restoration plan by maximally re-energizing the load through least switching operations. Moreover, an improved flexible switching pair operation is employed to maintain the radial structure of distribution system. Case studies are presented to verify the performance of the proposed strategy. Furthermore, the effects of integrating distributed energy resources and microgrid systems are analyzed in this dissertation.
Mahesh Illindala, Dr. (Advisor)
Jin Wang, Dr. (Committee Member)
Jiankang Wang, Dr. (Committee Member)
187 p.
Electrical Engineering
Distribution Systems; Distributed Energy Resources; Microgrids; Optimization; Planning Reserve Margin; Protection; Renewable; Resilience; Restoration;

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Citations

  • Yuan, C. (2016). RESILIENT DISTRIBUTION SYSTEMS WITH COMMUNITY MICROGRIDS [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1480478081556766

    APA Style (7th edition)

  • Yuan, Chen. RESILIENT DISTRIBUTION SYSTEMS WITH COMMUNITY MICROGRIDS. 2016. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1480478081556766.

    MLA Style (8th edition)

  • Yuan, Chen. "RESILIENT DISTRIBUTION SYSTEMS WITH COMMUNITY MICROGRIDS." Doctoral dissertation, Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1480478081556766

    Chicago Manual of Style (17th edition)

osu1480478081556766
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This open access ETD is published by The Ohio State University and OhioLINK.